We perform multiscale modelling and experiments to explore interactions, self-assembly and emergent dynamics in complex colloids. The term "complex colloids" is understood in a broad sense including inanimate and animate systems composed of interacting building blocks from nano- to microscale. We perform advanced Monte Carlo and Molecular Dynamics simulations in combination with analytical predictions of Statistical Mechanics to try to understand the complexity of the interactions resulting from nonlinear and many-body effects, multivalent binding, application of external fields, or properties of the medium. Besides the equilibrium structures, we explore non-equilibrium dynamics of colloidal and macromolecular systems, both theoretically and experimentally, e.g. time-resolved spectroscopy and imaging of protein-ion and protein-nanomaterial interactions. We also focus on novel methods to study functional substrates: designing and synthesizing complex molecular self-assembled architectures without relying on randomly deposited organic material at interfaces.